1. Field of the Invention
The present invention relates to an apparatus for detecting a motion of an image which may apply to a technique for compressing a moving picture.
2. Description of the Related Art
The inventors of the present invention know that a pattern matching technique has been widely studied for a practical use of searching a motion vector. The pattern matching technique is arranged to derive an accumulate D.sub.i,j of each coordinate (i, j) in the searching range between two pixel signal intensities X.sub.m,n and Y.sub.m,n of M.times.N pixels located between two frames contained in a two-dimensional image. For deriving the accumulate D.sub.i,j, the following expression (1) can be used. ##EQU1##
Then, as shown in FIG. 1, a minimum value is selected among the accumulates D.sub.i,j derived by the expression (1) and is output as a motion vector (consisting of a spatial location and a value). Next, assuming that a block to be searched is M.times.N and the searching range is L, as shown in FIG. 2, an absolute value of a difference between the block to be searched and the motion vector is calculated about a (M, N) pixel {(M.times.N).times.L} times.